1. Field of the Invention
The present invention is in the field of producing monolithic concrete modules, particularly in the form of inverted U shapes which may be combined to form a variety of building structures, and to apparatus for producing the same.
2. The Prior Art
As conducive to an understanding of the present invention, it is to be noted that the use of cast concrete building structures and subassemblies is increasing, due to the substantially lower cost thereof as contrasted with buildings fabricated by other methods, e.g. steel frames and curtain walls.
Numerous methods have been proposed for simplifying and expediting the formation of concrete modules in situ. The most commonly employed method involves the erection of wall forms of plywood, aluminum, etc., pouring of concrete therein to define vertical wall sections, aging of the cast wall sections until the same are structurally capable of supporting a load, stripping of the forms, subsequent positioning or casting of a slab member on the walls and the re-erection atop the slab of the wall forms for repetition of the steps hereinabove set forth.
As is well known, numerous disadvantages inhere in the procedures above described. Specifically, the forms used to cast concrete are typically expensive to rent and relatively time consuming to erect. The necessity for permitting such forms to remain in position until cure of the concrete has been substantially completed necessarily extends construction time, with attendant increased rental costs and labor costs.
Additionally, the subsequent positioning of a slab over a cured wall member results in a relatively weak joint or connection between the wall and the slab as compared, for instance, with a monolithically cast slab-wall construction.
In order to avoid the difficulties which inhere in the use of the standard construction systems above described, numerous attempts have been made to devise a practical and efficient means of forming in situ monolithic casting forms wherein at least two supporting side walls and slab may be simultaneously cast. Examples of the methods and apparatus created for such purpose are described in U.S. Pat. Nos. 3490,729; 3558,095; 3676,536; 3689,018; 3815,861; and 3822,853.
The methods and apparatuses as exemplified in the above referenced patents involve deficiencies of various sorts which have greatly hampered their commercial acceptance. A principal difficulty resides in the cumbersome and complex nature of the form mechanisms and their consequent great expense, together with the difficulty of positioning such forms, especially in multi-story building constructions.